Various technologies have been suggested for detecting and locating the position of vehicle occupants, particularly in relation to the deployment of pyrotechnic supplemental restraint devices such as frontal and side air bags. It has also been suggested to adapt the operation of various electrical accessories to the detected occupant position. For example, the capacity and airflow of an air conditioning system and the balance controls of an audio system may be adjusted based on the number of occupants and their location, electrically positioned mirrors and displays (such as head-up displays) may be adjusted for driver height, and so on; see, for example, the U.S. Pat. No. 4,625,329 to Ishikawa et al., issued on Nov. 25, 1986. Additionally, the occupant presence information can be utilized to limit the information supplied to a driver so as to minimize driver distraction while providing more detailed information to a non-driver occupant; see, for example, the U.S. Pat. No. 6,181,996 to Chou et al., issued on Jan. 30, 2001.
In systems of the type described above, practical considerations such as cost and packaging significantly limit the system content and capability. As a result, only the most essential of functions (such as disabling airbag deployment for a child) are actually utilized in all but the most expensive production vehicles. Nevertheless, there is a continuing and growing demand for a system that will reliably and cost-effectively deliver information regarding occupant position, location and activity, since it is thought that occupant safety could be considerably improved if such information were available.